From 615a99c2c20782daae5de38854025e2d40d85f29 Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Sun, 14 Jan 2018 15:10:13 -0800
Subject: RST reader: add aligned environment when needed in math.
rst2latex.py uses an align* environment for math in
`.. math::` blocks, so this math may contain line breaks.
If it does, we put the math in an `aligned` environment
to simulate rst2latex.py's behavior.
Closes #4254.
---
src/Text/Pandoc/Readers/RST.hs | 9 +++++++--
test/command/4254.md | 12 ++++++++++++
test/rst-reader.native | 2 +-
3 files changed, 20 insertions(+), 3 deletions(-)
create mode 100644 test/command/4254.md
diff --git a/src/Text/Pandoc/Readers/RST.hs b/src/Text/Pandoc/Readers/RST.hs
index ba5a24f8f..49cc3018c 100644
--- a/src/Text/Pandoc/Readers/RST.hs
+++ b/src/Text/Pandoc/Readers/RST.hs
@@ -972,11 +972,16 @@ extractCaption = do
legend <- optional blanklines >> (mconcat <$> many block)
return (capt,legend)
--- divide string by blanklines
+-- divide string by blanklines, and surround with
+-- \begin{aligned}...\end{aligned} if needed.
toChunks :: String -> [String]
toChunks = dropWhile null
- . map (trim . unlines)
+ . map (addAligned . trim . unlines)
. splitBy (all (`elem` (" \t" :: String))) . lines
+ -- we put this in an aligned environment if it contains \\, see #4254
+ where addAligned s = if "\\\\" `isInfixOf` s
+ then "\\begin{aligned}\n" ++ s ++ "\n\\end{aligned}"
+ else s
codeblock :: [String] -> Maybe String -> String -> String -> RSTParser m Blocks
codeblock classes numberLines lang body =
diff --git a/test/command/4254.md b/test/command/4254.md
new file mode 100644
index 000000000..e4cc5c6b0
--- /dev/null
+++ b/test/command/4254.md
@@ -0,0 +1,12 @@
+```
+% pandoc -f rst -t latex
+.. math::
+
+ x &= y\\
+ y &= z
+^D
+\[\begin{aligned}
+x &= y\\
+y &= z
+\end{aligned}\]
+```
diff --git a/test/rst-reader.native b/test/rst-reader.native
index 724c23b03..b0e51bd3f 100644
--- a/test/rst-reader.native
+++ b/test/rst-reader.native
@@ -317,7 +317,7 @@ Pandoc (Meta {unMeta = fromList [("author",MetaList [MetaInlines [Str "John",Spa
,Para [Math DisplayMath "E=mc^2"]
,Para [Math DisplayMath "E = mc^2"]
,Para [Math DisplayMath "E = mc^2",Math DisplayMath "\\alpha = \\beta"]
-,Para [Math DisplayMath "E &= mc^2\\\\\nF &= \\pi E",Math DisplayMath "F &= \\gamma \\alpha^2"]
+,Para [Math DisplayMath "\\begin{aligned}\nE &= mc^2\\\\\nF &= \\pi E\n\\end{aligned}",Math DisplayMath "F &= \\gamma \\alpha^2"]
,Para [Str "All",Space,Str "done."]
,Header 1 ("default-role",[],[]) [Str "Default-Role"]
,Para [Str "Try",Space,Str "changing",Space,Str "the",Space,Str "default",Space,Str "role",Space,Str "to",Space,Str "a",Space,Str "few",Space,Str "different",Space,Str "things."]
--
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